The Outcomes of Ponatinib Therapy in Patients With Chronic Myeloid Leukemia Resistant or Intolerant to Previous Tyrosine Kinase Inhibitors, Treated in Poland Within the Donation Program

Introduction: Tyrosine kinase inhibitors (TKIs) have greatly improved the treatment outcome for most patients with chronic myeloid leukemia (CML). Ponatinib is a new pan-inhibitor of TK active in resistant CML. This study aimed to evaluate the efficacy and safety of ponatinib in patients suffering from CML. Patients and methods: This multicenter, non-randomized, observational, retrospective study evaluated the efficacy and safety of ponatinib administered in adult CML patients in any disease phase, including those with a detected ABL T315I mutation, which were resistant or intolerant to previous-generation TKIs. The study comprised 43 patients benefiting from the ponatinib donation program who were treated in 16 Polish centers. Results: For patients who started treatment with ponatinib in chronic phase (CP) (n=23) and in accelerated phase (AP) (n=3) the median time on ponatinib was 19.5 months (range: 1.0-35.4), and 31.7 months (range: 31.0-34.1), respectively. All these patients were in CP after 1 month of treatment and at the end of observation – none of them progressed to AP or blastic phase (BP) during the study, meaning that progression-free survival was 100% at the end of observation (35.4 months). The estimated 2-year survival in this group of patients was 84%. For all 43 patients, median survival was not reached (lower quartile 6.3 months), and estimated 2-year survival was 60%. Conclusion: Our analysis confirmed ponatinib efficacy in a significant proportion of patients heavily pre-treated with TKIs achieving durable responses in both CP and AP/BP CML groups. Microabstract: Ponatinib is a new pan-inhibitor of tyrosine kinase active in resistant chronic myeloid leukemia (CML). Evaluation of outcomes in 43 patients confirmed ponatinib efficacy in a significant proportion of subjects heavily pre-treated with tyrosine kinase inhibitors achieving durable responses in both chronic phase and accelerated/blastic phase CML groups.